Background: Onychomycosis is a common disease that remains difficult to treat despite the introduction of new topical agents. Clinical trials on efinaconazole and tavaborole included 48 weeks' daily treatment regimens with a 4-week follow-up. It has been suggested that either a longer treatment regimen or longer follow-up would lead to even better results, primarily due to the time taken for the diseased nail to grow out, especially in those patients with more severe disease.
Objective: To investigate the impact of a longer follow-up period on the efficacy of efinaconazole 10% topical solution in patients with moderate-to-severe onychomycosis.
Methods: &Single center, open-labeled study in 23 subjects aged 18-80 years with a clinical and mycological diagnosis of moderate-to-severe dermatophyte toenail onychomycosis (40-75% clinical involvement). Subjects were treated with efinaconazole 10% solution, once-daily for 48 weeks, with two 12-week post-treatment follow-ups (at week 60 and 72). Primary efficacy endpoint was complete cure rate (0% clinical involvement of target toenail, and both negative potassium hydroxide examination and fungal culture). Secondary endpoints included mycologic cure rates and treatment success (defined as those patients who had at least a 50% improvement in affected toenail from baseline).
Results: Twenty-two subjects completed the study. Mean baseline age 59.4 years (range, 37-77), predominance of male subjects (73.9%). Median baseline severity 50% affected target toenail. At week 72, two subjects were complete cures and 56.5% of subjects achieved treatment success. There were no complete cures at week 48, but 39.1% achieved treatment success. Mycologic cure rates were 91.3% at week 48. Median percent affected target toenail reduced to 40%, and further to 25% (week 48 and 72, respectively). Treatment was well tolerated, with no adverse events related to medication.
Conclusions: This single-center phase 4 study supports previous data showing good efficacy and tolerability of efinaconazole in moderately severe onychomycosis. Continued reduction in disease severity post-treatment suggest that a longer follow-up of patients treated with efinaconazole would afford better efficacy results, as indicated by greater treatment success, and increase in number of subjects who became complete cures.